Numerical investigation on the hydrodynamic difference between internal and external turret-moored FLNG

Abstract

Motion responses of the floating liquefied natural gas (FLNG) hull and the mooring loads in a 100-year return environmental condition are predicted with the help of the well known coupled dynamic analysis code DeepC. A ship-shaped turret-moored FLNG moored by 4×3 chain-polyester-chain lines in 1.5 km depth of water is studied. Two types of turrets such as internal and external turrets, resulting from different locations of the turrets, are adopted respectively in the numerical simulations. Motion responses of the FLNG hull and forces of the mooring lines obtained from the internal turret case and external turret case are compared with each other. Significant differences are obtained. Statistic analysis is also used to analyze the comparison results, and effects of the turret location on the FLNG hydrodynamic characteristics are summed up. The conclusion regarding the hydrodynamic differences between internal and external turret-moored FLNG systems would provide help for design of the FLNG system.

Foundation item: the China National Significant Science & Technology Research Program (No. 2008ZX05026-006)